Showing papers by "University of Queensland published in 1999"
TL;DR: In this paper, a detailed review of the corrosion mechanisms of magnesium alloys is presented, and the basis for the design of new alloys with improved corrosion properties is provided for improving the corrosion properties.
Abstract: The high strength to weight ratio of magnesium alloys makes them extremely attractive for applications in transport or aerospace technology. However, their corrosion behavior is a major issue and one reason why they are still not as popular as aluminum alloys. This papers reviews the corrosion mechanisms of magnesium and provides the basis for the design of new alloys with improved corrosion properties.
1,922 citations
TL;DR: The discovery of this missing lithotroph and its identification as a new, autotrophic member of the order Planctomycetales, one of the major distinct divisions of the Bacteria makes an important contribution to the problem of unculturability.
Abstract: With the increased use of chemical fertilizers in agriculture, many densely populated countries face environmental problems associated with high ammonia emissions. The process of anaerobic ammonia oxidation ('anammox') is one of the most innovative technological advances in the removal of ammonia nitrogen from waste water. This new process combines ammonia and nitrite directly into dinitrogen gas. Until now, bacteria capable of anaerobically oxidizing ammonia had never been found and were known as "lithotrophs missing from nature". Here we report the discovery of this missing lithotroph and its identification as a new, autotrophic member of the order Planctomycetales, one of the major distinct divisions of the Bacteria. The new planctomycete grows extremely slowly, dividing only once every two weeks. At present, it cannot be cultivated by conventional microbiological techniques. The identification of this bacterium as the one responsible for anaerobic oxidation of ammonia makes an important contribution to the problem of unculturability.
1,475 citations
Centers for Disease Control and Prevention1, Pasteur Institute2, United States Army Medical Research Institute of Infectious Diseases3, University of Queensland4, Animal and Plant Health Inspection Service5, Ministry of Agriculture and Rural Development6, New York State Department of Environmental Conservation7, Wildlife Conservation Society8
TL;DR: In late summer 1999, an outbreak of human encephalitis occurred in the northeastern United States that was concurrent with extensive mortality in crows (Corvus species) as well as the deaths of several exotic birds at a zoological park in the same area.
Abstract: In late summer 1999, an outbreak of human encephalitis occurred in the northeastern United States that was concurrent with extensive mortality in crows (Corvus species) as well as the deaths of several exotic birds at a zoological park in the same area. Complete genome sequencing of a flavivirus isolated from the brain of a dead Chilean flamingo (Phoenicopterus chilensis), together with partial sequence analysis of envelope glycoprotein (E-glycoprotein) genes amplified from several other species including mosquitoes and two fatal human cases, revealed that West Nile (WN) virus circulated in natural transmission cycles and was responsible for the human disease. Antigenic mapping with E-glycoprotein-specific monoclonal antibodies and E-glycoprotein phylogenetic analysis confirmed these viruses as WN. This North American WN virus was most closely related to a WN virus isolated from a dead goose in Israel in 1998.
1,423 citations
27 Oct 1999
TL;DR: A method based upon the geometry of convex sets is proposed to find a unique set ofpurest pixels in an image, based on the fact that in N spectral dimensions, the N-volume contained by a simplex formed of the purest pixels is larger than any other volume formed from any other combination of pixels.
Abstract: The analysis of hyperspectral data sets requires the determination of certain basis spectra called 'end-members.' Once these spectra are found, the image cube can be 'unmixed' into the fractional abundance of each material in each pixel. There exist several techniques for accomplishing the determination of the end-members, most of which involve the intervention of a trained geologist. Often these-end-members are assumed to be present in the image, in the form of pure, or unmixed, pixels. In this paper a method based upon the geometry of convex sets is proposed to find a unique set of purest pixels in an image. The technique is based on the fact that in N spectral dimensions, the N-volume contained by a simplex formed of the purest pixels is larger than any other volume formed from any other combination of pixels. The algorithm works by 'inflating' a simplex inside the data, beginning with a random set of pixels. For each pixel and each end-member, the end-member is replaced with the spectrum of the pixel and the volume is recalculated. If it increases, the spectrum of the new pixel replaces that end-member. This procedure is repeated until no more replacements are done. This algorithm successfully derives end-members in a synthetic data set, and appears robust with less than perfect data. Spectral end-members have been extracted for the AVIRIS Cuprite data set which closely match reference spectra, and resulting abundance maps match published mineral maps.
1,284 citations
VU University Amsterdam1, University of Pennsylvania2, University of Maryland, Baltimore3, Cornell University4, New Mexico State University5, Qatar Airways6, Louisiana Tech University7, Université du Québec8, Stockholm School of Economics9, University of Buenos Aires10, University of Alberta11, University of Indonesia12, University of Queensland13, Bellevue University14, London Business School15, Western Illinois University16, University of Memphis17, Fudan University18, Boğaziçi University19, University of Reading20, University of South Africa21, Athens University of Economics and Business22, Ludwig Maximilian University of Munich23, University of Calgary24, University of Burgundy25, National Sun Yat-sen University26, Hong Kong Polytechnic University27, Indian Institute of Management Ahmedabad28, City University of Hong Kong29, Lincoln University (New Zealand)30, University of Lethbridge31, Wayne State University32, University College Dublin33, Indiana University34, Kuwait University35, Technion – Israel Institute of Technology36, University of Giessen37, The Chinese University of Hong Kong38, University of Zurich39, Fordham University40, Complutense University of Madrid41, University of Nebraska–Lincoln42, INCAE Business School43, National University of Malaysia44, Opole University45, Hong Kong Baptist University46, Tbilisi State University47, Ohio State University48, University of Wrocław49, Alexandria University50, University of San Francisco51, Melbourne Business School52, Bentley University53, University of Los Andes54, I-Shou University55, Johannes Kepler University of Linz56, International Labour Organization57, Smith College58, Copenhagen Business School59, Chungnam National University60, National University of Singapore61, Tilburg University62, Hong Kong University of Science and Technology63, Thammasat University64, Sewanee: The University of the South65, FernUniversität Hagen66, Soochow University (Suzhou)67, University of St. Gallen68, Kumamoto University69
TL;DR: In this paper, the authors focus on culturally endorsed implicit theories of leadership (CLTs) and show that attributes associated with charismatic/transformational leadership will be universally endorsed as contributing to outstanding leadership.
Abstract: This study focuses on culturally endorsed implicit theories of leadership (CLTs). Although cross-cultural research emphasizes that different cultural groups likely have different conceptions of what leadership should entail, a controversial position is argued here: namely that attributes associated with charismatic/transformational leadership will be universally endorsed as contributing to outstanding leadership. This hypothesis was tested in 62 cultures as part of the Global Leadership and Organizational Behavior Effectiveness (GLOBE) Research Program. Universally endorsed leader attributes, as well as attributes that are universally seen as impediments to outstanding leadership and culturally contingent attributes are presented here. The results support the hypothesis that specific aspects of charismatic/transformational leadership are strongly and universally endorsed across cultures.
1,227 citations
TL;DR: The theoretical and empirical foundations of a unique multilevel parenting and family support strategy designed to reduce the prevalence of behavioral and emotional problems in preadolescent children are outlined.
Abstract: This paper outlines the theoretical and empirical foundations of a unique multilevel parenting and family support strategy designed to reduce the prevalence of behavioral and emotional problems in preadolescent children. The program known as Triple P-Positive Parenting Program is a multilevel system of family intervention, which provides five levels of intervention of increasing strength. These interventions include a universal population-level media information campaign targeting all parents, two levels of brief primary care consultations targeting mild behavior problems, and two more intensive parent training and family intervention programs for children at risk for more severe behavioral problems. The program aims to determine the minimally sufficient intervention a parent requires in order to deflect a child away from a trajectory towards more serious problems. The self-regulation of parental skill is a central construct in the program. The program uses flexible delivery modalities (including individual face-to-face, group, telephone assisted, and self-directed programs) to tailor the strength of the intervention to the requirements of individual families. Its multidisciplinary, preventive and community-wide focus gives the program wide reach, permitting the targeting of destigmatized access points through primary care services for families who are reluctant to participate in parenting skills programs. The available empirical evidence supporting the efficacy of the program is discussed and its implications for research on dissemination are discussed.
1,109 citations
TL;DR: The sequence of the euchromatic part of human chromosome 22 is reported, which consists of 12 contiguous segments spanning 33.4 megabases, contains at least 545 genes and 134 pseudogenes, and provides the first view of the complex chromosomal landscapes that will be found in the rest of the genome.
Abstract: Knowledge of the complete genomic DNA sequence of an organism allows a systematic approach to defining its genetic components. The genomic sequence provides access to the complete structures of all genes, including those without known function, their control elements, and, by inference, the proteins they encode, as well as all other biologically important sequences. Furthermore, the sequence is a rich and permanent source of information for the design of further biological studies of the organism and for the study of evolution through cross-species sequence comparison. The power of this approach has been amply demonstrated by the determination of the sequences of a number of microbial and model organisms. The next step is to obtain the complete sequence of the entire human genome. Here we report the sequence of the euchromatic part of human chromosome 22. The sequence obtained consists of 12 contiguous segments spanning 33.4 megabases, contains at least 545 genes and 134 pseudogenes, and provides the first view of the complex chromosomal landscapes that will be found in the rest of the genome.
1,075 citations
TL;DR: Conditional moment closure (CMC) as mentioned in this paper is a well-known method for the prediction of turbulent reacting flows, with particular emphasis on combustion, and has been used extensively in the literature.
877 citations
TL;DR: Self-identity significantly predicted behavioural intention, a relationship that was not dependent on the extent to which the behaviour had been performed in the past, and the relationship between perceived behavioural control and intention was strongest for low identifiers.
Abstract: The aim of the present study was to examine further the role that self-identity plays in the theory of planned behaviour and, more specifically, to: (1) examine the combined effects of self-identity and social identity constructs on intention and behaviour, and (2) examine the effects of self-identity as a function of past experience of performing the behaviour. The study was concerned with the prediction of intention to engage in household recycling and reported recycling behaviour. A sample of 143 community residents participated in the study. It was prospective in design: measures of the predictors and intention were obtained at the first wave of data collection, whereas behaviour was assessed two weeks later. Self-identity significantly predicted behavioural intention, a relationship that was not dependent on the extent to which the behaviour had been performed in the past. As expected, there was also evidence that the perceived norm of a behaviourally relevant reference group was related to behavioural intention, but only for participants who identified strongly with the group, whereas the relationship between perceived behavioural control (a personal factor) and intention was strongest for low identifiers.
872 citations
TL;DR: Cutaneous squamous- cell carcinoma, but not basal-cell carcinoma seems to be amenable to prevention through the routine use of sunscreen by adults for 4.5 years, and there was no beneficial or harmful effect on the rates of either type of skin cancer, as a result of betacarotene supplementation.
872 citations
TL;DR: It is reported that Cu(II) markedly potentiates the neurotoxicity exhibited by Abeta in cell culture, suggesting that certain redox active metal ions may be important in exacerbating and perhaps facilitating Abeta-mediated oxidative damage in Alzheimer's disease.
TL;DR: The structural features of the two apparent subfamilies of the CCK peptides which may be significant for the likely defense related role of these peptides within plants are defined.
TL;DR: It is suggested that increasing body mass index has a role in the pathogenesis of steatosis in chronic hepatitis C and that Steatosis may contribute to fibrosis.
TL;DR: The results indicate that the mechanism of preparatory spinal control is altered in people with lower back pain for movement at a variety of speeds.
TL;DR: It is found that in the genetic disease Niemann–Pick type C and in drug-treated cells that mimic NPC, cholesterol accumulates in late endosomes and sorting of the lysosomal enzyme receptor is impaired.
Abstract: The fate of free cholesterol released after endocytosis of low-density lipoproteins remains obscure. Here we report that late endosomes have a pivotal role in intracellular cholesterol transport. We find that in the genetic disease Niemann-Pick type C (NPC), and in drug-treated cells that mimic NPC, cholesterol accumulates in late endosomes and sorting of the lysosomal enzyme receptor is impaired. Our results show that the characteristic network of lysobisphosphatidic acid-rich membranes contained within multivesicular late endosomes regulates cholesterol transport, presumably by acting as a collection and distribution device. The results also suggest that similar endosomal defects accompany the anti-phospholipid syndrome and NPC.
TL;DR: The past year has brought compelling evidence that microdomains indeed exist in living cells, and several recent papers have suggested that caveolae, which are considered to be a specific form of raft, and caveolins, the major membrane proteins of caveolai, are involved in the dynamic cholesterol-dependent regulation of specific signal transduction pathways.
TL;DR: It is concluded that a pool of surface E-cadherin is constantly trafficked through an endocytic, recycling pathway and that this may provide a mechanism for regulating the availability of E- cadherIn for junction formation in development, tissue remodeling, and tumorigenesis.
Abstract: E-Cadherin plays critical roles in many aspects of cell adhesion, epithelial development, and the establishment and maintenance of epithelial polarity. The fate of E-cadherin once it is delivered to the basolateral cell surface, and the mechanisms which govern its participation in adherens junctions, are not well understood. Using surface biotinylation and recycling assays, we observed that some of the cell surface E-cadherin is actively internalized and is then recycled back to the plasma membrane. The pool of E-cadherin undergoing endocytosis and recycling was markedly increased in cells without stable cell-cell contacts, i.e., in preconfluent cells and after cell contacts were disrupted by depletion of extracellular Ca2+, suggesting that endocytic trafficking of E-cadherin is regulated by cell-cell contact. The reformation of cell junctions after replacement of Ca2+ was then found to be inhibited when recycling of endocytosed E-cadherin was disrupted by bafilomycin treatment. The endocytosis and recycling of E-cadherin and of the transferrin receptor were similarly inhibited by potassium depletion and by bafilomycin treatment, and both proteins were accumulated in intracellular compartments by an 18°C temperature block, suggesting that endocytosis may occur via a clathrin-mediated pathway. We conclude that a pool of surface E-cadherin is constantly trafficked through an endocytic, recycling pathway and that this may provide a mechanism for regulating the availability of E-cadherin for junction formation in development, tissue remodeling, and tumorigenesis.
TL;DR: In this article, a more complete understanding of grain refinement is presented, and the validity of the grain refinement paradigm shift toward the solute paradigm is presented. But, despite the extensive literature on grain refinement, there is not a consensus on the mechanism of grain refining in aluminum alloys.
Abstract: Despite the extensive literature on grain refinement, there is not a consensus on the mechanism of grain refinement in aluminum alloys. Recently, there has been a shift in understanding of the grain-refinement paradigm from purely being concerned with the nucleation event, called here the “nucleant paradigm,” to also being concerned with the effect of solute elements, or, the “solute paradigm,” on the final grain structure. This article is divided into two parts. In Part I, the literature underpinning both paradigms is explained, and the validity of the paradigm shift toward the solute paradigm as a more complete understanding of grain refinement is presented. Part II experimentally confirms the validity of the solute paradigm and details a mechanism which explains the need for both effective nucleants and a solute of a good segregating power in order to obtain grain refinement.
TL;DR: In this article, the importance of T-g in relation to drying process and dried foods is discussed, which results in an increased rate of physicochemical changes in dried products, such as sticking, collapse, caking, agglomeration, crystallization, loss of volatiles, browning and oxidation.
06 Jul 1999
TL;DR: Angeline et al. as mentioned in this paper proposed a number of techniques to improve the standard particle swarm optimisation (PSO) algorithm, which has some attractive properties, but its solution quality has been somewhat inferior to other evolutionary optimisation algorithms.
Abstract: In recent years population based methods such as genetic algorithms, evolutionary programming, evolution strategies and genetic programming have been increasingly employed to solve a variety of optimisation problems. Recently, another novel population based optimisation algorithm - namely the particle swarm optimisation (PSO) algorithm, was introduced by R. Eberhart and J. Kennedy (1995). Although the PSO algorithm possesses some attractive properties, its solution quality has been somewhat inferior to other evolutionary optimisation algorithms (P. Angeline, 1998). We propose a number of techniques to improve the standard PSO algorithm. Similar techniques have been employed in the context of self organising maps and neural-gas networks (T. Kohonen, 1990; T.M. Martinez et al., 1994).
TL;DR: In this paper, the geochronological evolution of early Archaean gneisses from southern West Greenland is reassessed using the well-established cathodoluminescence imaging method both to reveal previously undocumented complex zircon growth histories and to control positioning of ion-microprobe U-Th-Pb analyses.
TL;DR: The chelators were more effective in extracting Aβ from Alzheimer's disease brain tissue than age-matched controls, suggesting that metal ions differentiate the chemical architecture of amyloid in Alzheimer’s disease.
TL;DR: Results provide a crucial link between the cholesterol-trafficking role of caveolin and its postulated role in signal transduction through cholesterol-rich surface domains and provide direct evidence that H-Ras and K-RAs, which are targeted to the plasma membrane by different carboxy-terminal anchors, operate in functionally distinct microdomains of the plasma membranes.
Abstract: The plasma membrane pits known as caveolae have been implicated both in cholesterol homeostasis and in signal transduction. CavDGV and CavKSY, two dominant-negative amino-terminal truncation mutants of caveolin, the major structural protein of caveolae, significantly inhibited caveola-mediated SV40 infection, and were assayed for effects on Ras function. We find that CavDGV completely blocked Raf activation mediated by H-Ras, but not that mediated by K-Ras. Strikingly, the inhibitory effect of CavDGV on H-Ras signalling was completely reversed by replenishing cell membranes with cholesterol and was mimicked by cyclodextrin treatment, which depletes membrane cholesterol. These results provide a crucial link between the cholesterol-trafficking role of caveolin and its postulated role in signal transduction through cholesterol-rich surface domains. They also provide direct evidence that H-Ras and K-Ras, which are targeted to the plasma membrane by different carboxy-terminal anchors, operate in functionally distinct microdomains of the plasma membrane.
TL;DR: This analysis uses ontology, which is the branch of philosophy dealing with models of reality, to analyze the meaning of common conceptual modeling constructs and derives rules for the use of relationships in entity-relationship conceptual modeling.
Abstract: Conceptual models or semantic data models were developed to capture the meaning of an application domain as perceived by someone. Moreover, concepts employed in semantic data models have recently been adopted in object-oriented approaches to systems analysis and design. To employ conceptual modeling constructs effectively, their meanings have to be defined rigorously. Often, however, rigorous definitions of these constructs are missing. This situation occurs especially in the case of the relationship construct. Empirical evidence shows that use of relationships is often problematical as a way of communicating the meaning of an application domain. For example, users of conceptual modeling methodologies are frequently confused about whether to show an association between things via a relationship, an entity, or an attribute. Because conceptual models are intended to capture knowledge about a real-world domain, we take the view that the meaning of modeling constructs should be sought in models of reality. Accordingly, we use ontology, which is the branch of philosophy dealing with models of reality, to analyze the meaning of common conceptual modeling constructs. Our analysis provides a precise definition of several conceptual modeling constructs. Based on our analysis, we derive rules for the use of relationships in entity-relationship conceptual modeling. Moreover, we show how the rules resolve ambiguities that exist in current practice and how they can enrich the capacity of an entity-relationship conceptual model to capture knowledge about an application domain.
TL;DR: No outcomes improved significantly and nine worsened significantly for some conditions, and further studies need to be done to establish evidence for the benefit or harm of bed rest as a treatment.
TL;DR: In this paper, it is argued that employees' attraction to and trust in their peers, and their organization-based self-esteem mediate the effect of demographic dissimilarity on organizational citizenship behavior (OCB).
Abstract: It is argued that employees' attraction to and trust in their peers, and their organization-based self-esteem mediate the effect of demographic dissimilarity on organizational citizenship behavior (OCB). Data from a held study support a model in which the relationship between demographic dissimilarity and OCB is contingent on demographic characteristics and work group composition and mediated to an extent by the proposed mediators. The influence of race dissimilarity varied in strength for white and minority employees, but the influence of age dissimilarity varied in direction for older and younger employees.
TL;DR: In this article, changes in a bank's market share of deposits are explored as a means of determining the extent to which efficiency gains are passed on to the public, and evidence from the merger cases studied supports the reports of others that acquiring banks are more efficient than target banks.
Abstract: Operating efficiencies, employee productivity, profit performance and average relative efficiency (using Data Envelopment Analysis) were measured for Australian trading banks from 1986 to 1995. Changes in a bank’s market share of deposits is explored as a means of determining the extent to which efficiency gains are passed on to the public. In general, efficiencies rose in the post-deregulation period. Evidence from the merger cases studied supports the reports of others that acquiring banks are more efficient than target banks. However, the acquiring bank does not always maintain its pre-merger efficiency. Decision-makers ought to be more cautious in promoting mergers as a means to enjoying efficiency gains. There is mixed evidence on the extent to which the benefits of efficiency gains are passed on to the public.
TL;DR: Heterogeneity in the promoter region of the IL‐10 gene has a role in determining the initial response of chronic hepatitis C to IFN‐α therapy and patients who are genetically predisposed to high IL-10 production have a poor response to IFn‐α and may benefit from additional treatment strategies designed to enhance a T‐helper type 1 (Th1) response.
TL;DR: Quenching analysis of RLCs revealed large qE development in long-term dark adapted leaves accounting for the low ETRs, and Actinic irradiance exposures and saturating flashes affected leaves with different irradiance histories differently.
Abstract: Photosynthetic electron transport rates (ETR), calculated from chlorophyll fluorescence parameters, were compared in long term light and dark adapted as well as photoinhibited Pisum sativum leaves using a novel chlorophyll fluorescence method and a new instrument: rapid light curves (RLC) generated with the MINI-PAM. RLCs are plots of ETRs versus actinic irradiances applied for 10 s. Large changes in maximum electron transport rates (ETRmax) were observed when leaves were shifted from dark to moderate light, or from dark to photoinhibitory light and vice versa. Maximum ETRs were very low following long term dark adaptation, but increased to maximum levels within 8 to 15 minutes of illumination. It took more than 3 hours, however, to return irradiance-exposed leaves to the fully dark adapted state. Quenching analysis of RLCs revealed large qE development in long-term dark adapted leaves accounting for the low ETRs. Leaves photoinhibited for 3 hours had similarly reduced ETRs. In these leaves, however, qI was largely responsible for this reduction. Actinic irradiance exposures and saturating flashes affected leaves with different irradiance histories differently.
TL;DR: Teacher attrition is generally positioned within research addressing teacher shortage, wastage of resources and expertise, as well as that concerning teachers’ lowly status and poor working conditions as mentioned in this paper.